Soluble cutting oils



Patented Aug. 7, 195T SOLUBLE CUTTING OILS Thomas Walton Dixon, Sarnia, Ontario, Canada, assignor to Standard Oil Development Company, a corporation of Delaware No Drawing. Application March 6, 1948, Serial No. 13,533

4 Claims.

This invention pertains to soluble cutting oils and more particularly to transparent soluble oils which are compounded in a manner to minimize foaming. The invention pertains further to a method or process for inhibitingloaming in cutting oils and analogous types of lubricating compositions.

In the prior art certain compositions known as soluble cutting oils have met with marked commercial success because they are economical for use, are quite transparent, and they have desirable load-carrying properties which are necessary in many types of. machiningloperations.

The so-called soluble cuttingoils are readily emulsifiable inwater so that small quantities of oil may be mixed with relatively large quantities of watertoprovide a cuttingcompound which has high heat capacity and at the same time good extreme pressure properties. In machining operations it is also desirable to have as transparent a cutting oil as possible in order that the work upon which operations'are being performed may not be obscured by the lubricating material. Hence there have: been developed in the prior art transparent cutting oils having desirable properties such as high load-carrying ability, ready emulsification with water, and the like.

Inasmuch as cutting oils are commonly circulated and recirculated it is desirable that they not only be light or transparent in color but also that they be relatively free from foam which would interfere with effective lubricating and also, to a considerable extent, with visibility. It

has previously been suggested in Patent No. 2,275,007 to Larsen et al. that certain silicone and silicate polymers may be added in small proportions to certain oils and other organic materials so as to minimize their tendency toward. foaming when subjected to vigorous mechanical action. The silicon compound polymers which have been suggested in the Larsen patent, and in the prior art, have provedito have good antifoaming qualities but they areexpensive and are not" the most suitable for use in soluble cutting cilsof the character referred to above.

It is an object of the present invention to improve the antifoaming properties of transparent cuttingoils and related compositions and particularly to improve the antifoaming properties of solublecutting oils which contain substantial quantities of petroleum sulfonates as emulsifiers, together with extreme pressure materials and the like.

Some difficulty has been encountered in the prior art in adding silicone polymers to soluble cutting oils during manufacture. Silicones could not be added during .saponification, as Where sodium hydroxide is added to an oil containing petroleum sulfonates and rosin because theantifoaming agent tends to cause settling or precipitation of the soap which results from the saponis fioation treatment. Furthermore, inasmuch as prior art antifoaming agents of the silicone polymer type are not appreciably soluble ,or dispersible in mineral oils, it has not been satisfactory to add the silicone polymer as a slurry after the soluble oil had cooled following the saponification.

According to the present invention, it has been found, however, that in the presence of irom 0.005 to 0.1 or 0.2%asuitable amine such as triethanolamine or dicyclohexylamine, the silicone polymer antifoaming agent may be added during saponification without precipitating the other ingredients of the soluble oil. Other similar amines such as ethanolamine, diethanolamine, mono heptyl diphenyl amine, di-heptyl diphenyl amine, cyclc-hexyl amine, diphenyl amine and triphenyl amine may be used. These obviously comprise the simple and mixed lower alkylol amines, the phenyl amines and the cyclohexyl amines, at least. Also, mixtures of any of the foregoing may be employed. Likewise, a trace of the order-of 0.005% to 0.1% or 0.2% of a phenol, such as diamyl phenol produces a similar effect. Terti-- ary butyl phenol also may be used. In both cases, furthermore, a much smaller quantity of the silicone polymer antifoaming agent is required than when it is added as a slurry.

The preferred silicone employed in this invention is a light fairly viscous one which retains its honey-like consistency over a wide temperature range. It is a colorless, translucent compound, lighter than water and insoluble in water. One such compound is now available on the market, being sold by the Dow Corning Company as Antifoam A. For ease of dispersion, 0.008 to 0.01% of a suitable amine or phenol, of the types described above, appearsto be desirable for use preferably with quantities of not more than 0.05% of the silicone polymer. ;A suitable glycolmonoalkyl ether, wherein the mono-alkyl groupis a C2 to C4 group, should be used as a mutual solvent in proportions ofup to 3 all these percentages being based onthetotal composition. The latter serves both as a mutual solvent-and as an addi-g tional dispersant for the oil insolub le'silicone' compound.

The improvements secured mentioned above, are enhanced by the addition of very small quantites of amine or phenol which by the silicones, as"

3 greatly lessens the tendency of the emulsion to free emulsified oil. This tendency is also further reduced by substituting a glycol ether for the alcohol mutual solvents which are commonly used in prior art soluble oils. About half as much glycol mono-ethyl ether, or the corresponding glycol mono-butyl ether is used as alcohol in the prior art. In other words, the substitution of glycol mono-alkyl ethers for ordinary alcohol makes possible the use of a smaller amount of mutual solvent and at the same time improves the quality of the emulsion produced when the soluble oil is dispersed or dissolved in water. known in the prior art, soluble oils of this general character are used in proportions which may range from one part of soluble oil to 10 to 40 parts of water.

It has been noted that the use of excessive amounts of the dispersing agent tends to invert the emulsion and materially reduces its transparency. However, the dispersibility of silicone polymer antifoaming agents, in quantities not exceeding 0.05% based upon the total soluble oil composition is much superior in a soluble oil containing a triethanolamine, etc, a phenol such as di-amyl phenol plus glycol mono-alkyl ether. By this means foaming tendencies of soluble oils may be inhibited" to the same degree by the use of a considerably smaller amount of the expensive silic'one polymer inhibitor.

One present commercial formulation for a transparent emulsifiable cutting oil with excessive tendency to foam formation is shown below:

42.10% petroleum sulfonates (65:35 oil solution, type not important, may be sodium, calcium,

- etc.)

10.10 rosin (any rosin, natural or synthetic, with about 60% abietic acid content) 1.20% sodium hydroxide 215% water 4.30% alcohol 40.15% paraffinic oil with viscosity 44 S. S. U.

1' at F.

This finished product oil has a viscosity at 210 F.

of between 600-900 S. S. U. with a free acid content of about 0.5-0.7 as oleic acid.

. A composition according to the present invention-having substantially the same major ingredients as that given above, involves replacing the alcohol by a smaller quantity of a glycol monoalkyl ether suchas glycol mono-butyl ether and introducingsmall quantities of antifoaming agent and amine modifier. This product is very markedly superior in antifoaming properties.

The composition of a particular example is as follows: 1 v

42.10% petroleum sulfonates (65:35)

10.10% rosin 1.20% sodium hydroxid 2.15% water 2.50% glycol mono-butyl ether 41.89% paralifinic oil with viscosity 44 S. S. U. at

0.05 silicone polymer antifoaming agent 0.01 triethanolamine or dicyclohexylamine sification agent, may vary considerably, for ex- As is well ample, from as little as 5 to as much as 50% of the total oil. The rosin and sodium hydroxide (rosin soap) content may be varied considerably, from 2 to 15%, the mineral oil base may be of various grades and viscosities and various extreme pressure additives and other modifiers may be introduced to impart specific properties to the oil as will be understood by those skilled in the art. This invention has to do particularly with the enhancement of foam inhibiting qualities made possible by the use of amines such as triethanolamine, dicyclohexylamine and others listed above, or phenols such as diamyl phenol or the like, by the use of a suitable glycol mono-alkyl ether to replace the mutual solvent alcohol which has been used in analogous compositions in the past. It will be understood, of course, that any two or more of these materials may be used in combination so long as the proportions employed do not materially change the characteristics of the cutting oil nor interfere with the foam inhibiting properties of the silicone additive.

In general, the composition of the present invention comprises 20 to 70% mineral oil by weight, 10 to 50% petroleum sulfonate (oil soluble), to 15% soap (preferably rosin soap and preferably at least 2%) 1 to of a mutual solvent glycol alkyl ether, 0.01 to 0.1% (preferably 0.01 to 0.05%) of silicone polymer, and 0.005 to 0.2% of a modifier which may be an amine, or a phenol, or both as described above.

What is claimed is:

l. A soluble cutting oil consisting essentially of to 50% petroleum sulfonate, 2 to rosin soap, to mineral oil, 1 to 5% of C2 to C4 mono-alkyl ether of glycol as a mutual solvent, 0.01 to 0.1% of a silicone polymer and 0.005 to 0.2 of an amine selected from the group which consists of lower alkylol amines, phenyl amines and cyclohexyl amines, a modifier for dispersing said silicone polymer in said oil.

2. A composition according to claim 1 wherein said modifier is triethanolamine and said mutual solvent is a glycol mono butyl ether.

3. A composition according to claim 1 wherein said modifier is dicyclohexylamine and said mutual solvent is a glycol mono-butyl ether.

4. A transparent cutting oil having approximately the following composition:

THOMAS WALTON DIXON.

REFERENCES CITED The following references are of record in the file of this patent:

} (reacted to form a soap) UNITED STATES PATENTS Number I Name Date 2,320,263 Carlson May 25, 1943 2,328,727 Langer Sept. 7, 1943 2,375,007 Larsen May 1, 1945' 2,406,671 -Diamond Aug. 27, 1946 2,435,124 .Boll-inger ':Jan. 27, 1948,

2,470,913 Bjorksten May 24, 1949 

1. A SOLUBLE CUTTING OIL CONSISTING ESSENTIALLY OF 10 TO 50% PETROLEUM SULFONATE, 2 TO 15% ROSIN SOAP, 20 TO 70% MINERAL OIL, 1 TO 5% OF C2 TO C4 MONO-ALKYL ETHER OF CLYCOL AS A MUTUAL SOLVENT, 0.01 TO 0.1% OF A SILICONE POLYMER AND 0.005 TO 0.2% OF AN AMINE SELECTED FROM THE GROUP WHICH CONSISTS OF LOWER ALKYLOL AMINES, PHENYL AMINES AND CYCLOHEXYL AMINES, A MODIFIER FOR DISPERSING SAID SILICONE POLYMER IN SAID OIL. 